Question 1
A gold wire has a diameter of 1.00 mm. What length of this wire contains exactly 1.00 mol of gold? (density of Au = 17.0 g/cm
3)
◦ 2630 m
◦ 3.69 m
◦ 251 m
◦ 14.8 m
◦ 62.7 m
Question 2
A mass spectrometer works by ionizing atoms or molecules, and then accelerating them through oppositely charged plates. The mass is obtained by
◦ measuring the force of impact on a detecting screen, and then calculating the mass using force = mass × acceleration.
◦ suspending the ions in an applied electric field, and then calculating mass by the setting the downward gravitational force equal to the upward electrostatic force.
◦ measuring the magnitude of deflection as the ions pass through a magnetic field to obtain the charge-to-mass ratio, and then calculating the mass from that ratio.
◦ measuring the time it takes for the ions to hit the detector at a known distance to calculate the acceleration, and then calculating mass from force = mass × acceleration.
Shape changes in molecules
Water Molecules Surround Ions
Water Molecules
Yeast aspartyl tRNA synthetase complexed with two molecules of tRNAAsp
Mass Wasting Triggers
Mass Extinctions